#include<stdio.h> 
int main()
{
	double x = 0, y = 0;
	scanf("%lf %lf", &x, &y);
	if ( (-1 <= x && x <= 1) && (-1 <= y && y <= 1) )
	{
		printf("Yes");
	}
	else {
		printf("No");
	}
	return 0;
}
